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Course: Physics library > Unit 18
Lesson 2: Discovery of magnetic fieldsMagnetic permeability
What happens to the magnetic field of a magnet in the presence of a another material which is attracted to it. Why does this happen? Created by Brit Cruise.
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- How did you get the iron filings off of the magnet?(36 votes)
- get a stronger electromagnet so the fillings stick to there, then demagnetize the electromagnet :)(35 votes)
- I get that In electromagnetism, 'permeability' is the measure of the ability of a material to support the formation of a magnetic field within itself (wikipedia definition).
But what does that mean in simpler terms?
When a material enters in contact with a magnetic field it has an ability to form a magnetic field as well ? And why does that happen ? How?
Sorry for the epistemological kind of question, I'm really curious about this.(5 votes)- It's just a measure of how well the magnetic field passes through the material. Some materials let it pass easily, they have high permeability. Others block it more. They have low permeability.(3 votes)
- How come the iron bar did not collect any iron fillings?? Did the red magnet "hog" all of the magnetism, or was it because the iron bar was already attracted to the red magnet??(3 votes)
- because the metal was attached to both the poles so the metal was probably neutralized as we seen in the previous videos.(3 votes)
- As the video says "to the material or block which is in contact to the magnet, iron fillings are not attracted.......in the same way when 1 iron filling is in contact with magnet it should not attract the other 1....but they are forming a chain !! how is it possible..(3 votes)
- Will anyone tell me what basically is the meaning of this presentation?(3 votes)
- Notice that when the bar is attached to the magnet the distance over which the force interacts with the iron filings decreases. It seems as though the steel bar is acting as a magnetic shield....(1 vote)
- If iron filings clump up on the steel plate when it is on the magnet, how does the steel plate react to the iron filings?(3 votes)
- In this video does anyone know what material was used to "block" the magnetism?(2 votes)
- It almost looks as if when he puts the magnet down, the iron filings are repelled and they create a space around it...but that seems wrong. They didn't just all attract to the magnet, right? It didn't look like there were that much filings on the magnet...(1 vote)
- The field weakens, the further away from the magnet you are. So yes, the filings closer in were attracted, whereas the ones further out were not. Sort of like the event horizon on a black hole, there is a point at which you cannot escape.(2 votes)
- Athow do you get the iron fillings and how do lots of iron fillings become something that looks like it is some piece of cloth wrapped over the magnet? 1:33(1 vote)
- Why did the piece of metal got magnetic when it was stuck on the magnet?(1 vote)
Video transcript
Iron fillings